Coated article

ABSTRACT

A coated article has a coating which is an at least partially cured coating composition prepared from a polyurea-polyurethane acrylate dispersion.

This is a division of application Ser. No. 427,397, filed Sept. 29,1982, now U.S. Pat. No. 4,477,405, which is a division of applicationSer. No. 336,226 filed Dec. 31, 1981, now U.S. Pat. No. 4,425,468.

BACKGROUND OF THE INVENTION

The present invention relates to polyurea-polyurethane acrylate polymerdispersions; their method of preparation and their use in coating andmolding applications.

It has been known heretofore that the utilization of acrylate terminatedurethane polymers in coating and molding compositions results inexceptional coating performance properties such as, for example, aunique combination of hardness and flexibility, abrasion resistance,solvent resistance, good application and adhesion properties and goodfinal film appearance. Moreover, it has also been generally known thatthe presence of urea groups in polyurethane polymers further adds to thealready excellent properties described above, for example, impactresistance, tear resistance, thermal stability and enhancement of thecombination of hardness and flexibility. However, whereas, it ispredominantly desirable to introduce urea groups into a urethane polymersystem, depending upon the mode of introduction of these groups, theycan result in disadvantageous properties in the final polymer.

Usually, urea-linked urethane polymers are formed by the use of an aminefunctional group-containing compound at the urea-forming step. Forexample, U.S. Pat. No. 4,097,439 discloses a process in which adiisocyanate is reacted first with a diol to form anisocyanate-terminated urethane followed by chain extension with adiamine and end-capping with hydroxyl-containing acrylate to form aurethane-urea acrylate polymer. German Pat. No. 2,404,239 is alsodirected to a polyurethane-polyurea resin formed from the reaction of apolyisocyanate with a polyol to form a polyurethane prepolymer whichcontains isocyanate groups, and then reacting this prepolymer withpolyamine to form the resin product. Using amine-containing compounds inthis manner as a device to introduce urea groups into a polymer chainhas two significant effects. First the resultant polymer is prepared asa solution polymer and second there are adverse effects on therheological properties, namely viscosity and thixotropy are markedlyincreased. This poses practical difficulties in coating and moldingcompositions such as Injection Molding wherein the molding compositionis pumped from a storage receptacle to the molding machines. In areas ofthe pumping system where shearing forces are minimal, the compositiontends to set up gel networks and solidify thus clogging the system andresulting in equipment malfunction and work delays. This phenomenom isfurther intensified with the use of aromatic polyisocyanates and/orethylenically unsaturated monomeric diluents such as styrene and methylmethacrylate. There is therefore a need to produce a terminalethylenically unsaturated urea-urethane polymer which has all of thebeneficial properties described above but without the attendantrheological drawbacks.

In addition to the prior art mentioned above dealing with solutionpolymers, the article by Spitler and Lindsey, "PHD Polyols, A New Classof PUR Raw Materials", Journal of Cellular Plastics, January/February1981, pages 43-50, discloses polyol dispersions which consist ofparticles of polyurea dispersed in a polyether polyol, the polyureaformed from the reaction of a polyisocyanate with a polyamine.Urea-urethane polyol is formed as a result of some polyol reacting withpolyisocyanate followed by reaction with polyamine. Thesepolyurea-urethane polyol dispersions, however, do not contain ethylenicunsaturation.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided an articlehaving a coating on its outer surface which substantially and uniformlycovers the surface, the coating comprising an at least partially curedcoating composition which comprises a dispersion of the followingingredients in an ethylenically unsaturated monomer:

(i) a polymerizable ethylenically unsaturated urea-urethane polymerprepared by a process, which comprises:

A. reacting a polyisocyanate, at least a portion of which is adiisocyanate, with a polyfunctional amine containing primary and/orsecondary amino groups in the presence of a polyol, at least a portionof which is a polymeric polyol, free of ethylenic unsaturation and adiluent which is an ethylenically unsaturated compound free of activehydrogens, the equivalent ratio of isocyanate to active hydrogen in saidpolyol and said polyfunctional amine being within the range of 1.1 to2.0/1 and the equivalent ratio of polyol to polyfunctional amine beingwithin the range of 0.75 to 20/1, under conditions sufficient to form anNCO group-containing polyurea-polyurethane dispersed in an ethylenicallyunsaturated compound; followed by

B. reacting the NCO group-containing polyurea-polyurethane dispersionwith an active hydrogen-containing polymerizable ethylenicallyunsaturated compound under conditions sufficient to react theNCO-functionality with the active hydrogens thereby forming thepolymerizable ethylenically unsaturated urea-urethane polymerdispersion;

(ii) a catalyst, and

(iii) a mold release agent.

The polymers of the present invention are readily distinguished from theart-recognized polymers discussed previously. The polyureapolyurethanepolyol dispersions disclosed in the Journal article cited above are notethylenically unsaturated as are the polymers of the present invention.The lack of unsaturation restricts the use to which the polymers can beapplied. The polymers of the present invention are also distinguishedfrom the acrylate terminated urethane-urea polymers of aforementionedU.S. Pat. No. 4,097,439 and German Pat. No. 2,404,239 in that they aredispersion polymers having low viscosity and thixotropy rather than highviscosity, high thixotropy solution polymers disclosed in thereferences. Moreover, these art-recognized polymers are generally theresult of a sequential reaction; that is, the polyisocyanate is reactedfirst with a diol to form a urethane prepolymer, then chain extendedwith a diamine, and finally end-capped with acrylate. The process formaking the polymers of the present invention is distinguished from theaforedescribed art-recognized process in that it is not strictly asequential process. Rather a polyisocyanate is reacted with apolyfunctional amine in the presence of polyol free of ethylenicunsaturation, resulting in the formation of a dispersed polymer andbetter viscosity control. The dispersion polymers of the presentinvention, therefore, have all of the excellent performance propertiesassociated with urea-urethane polymers but in addition they also haveexcellent rheological properties making them especially appropriate formolding applications.

DETAILED DESCRIPTION OF THE INVENTION

As stated above, the polyurea-polyurethane dispersion polymers of thepresent invention comprise the reaction product of the followingessential ingredients: a polyisocyanate, a polyfunctional amine, apolyol free of ethylenic unsaturation, a diluent, and an activehydrogen-containing polymerizable ethylenically unsaturated compound.

The polyisocyanate component can be an aliphatic polyisocyanate,including a cycloaliphatic polyisocyanate or an aromatic polyisocyanate;preferably a diisocyanate is employed. Useful aliphatic diisocyanatesinclude ethylene diisocyanate, 1,2-diisocyanatopropane,1,3-diisocyanatopropane, 1,6-diisocyanatohexane, 1,4-butylenediisocyanate, 1,6-hexamethylene diisocyanate, lysine diisocyanate,1,4-methylene bis(cyclohexyl isocyanate) and isophorone diisocyanate.Useful aromatic diisocyanates include toluene diisocyanate,meta-xylene-diisocyanate, para-xylene-diisocyanate,4-chloro-1,3-phenylene diisocyanate, 1,5-tetrahydro-naphthalenediisocyanate, 4,4'-dibenzyl diisocyanate and 1,2,4-benzenetriisocyanate.

The polyfunctional amine component contains primary and/or secondaryamino groups; it can be a compound which is monofunctional with respectto amine and which has active hydrogen in addition to the aminehydrogens; e.g., hydroxyl groups. Preferably the polyfunctional amine isa polyamine, more preferably a diamine and preferably the polyfunctionalamine is cyclic. More preferably the polyfunctional amine is a cyclicdiamine. Useful polyfunctional amines include monoethanolamine, anammonia-hydroxyethyl acrylate adduct, m-phenylene-diamine,propylenediamine, ethylenediamine, diethylenetriamine, toluenediamine,isophoronediamine, N-methyl 1,3-propane diamine, poly(propyleneether)diamine and N, N'-dicyanoethyl poly(propylene ether)diamine;preferably isophoronediamine is utilized. The polyfunctional aminepreferably has a molecular weight within the range of 60 to 2000, morepreferably 60 to 1000, the molecular weight being determined on a numberaverage base.

Exemplary of the polyol component useful in preparing the claimeddispersion polymers are polymeric polyols, that is those having amolecular weight of 500 or more, preferably 500 to 5000, on a numberaverage basis and low molecular weight polyols, that is those having amolecular weight of 250 or less, preferably 62 to 250. Although it hasbeen specified that the molecular weight of the polymeric polyol can be500 or more, and the low molecular weight polyol less than 250, itshould be appreciated that polyols having molecular weights within theselimits can also be used. Broadly speaking, the molecular weight of thepolyol component should range from about 62 to 5000, the molecularweight being determined on a number average basis.

Examples of the low molecular weight polyols are propylene glycol,1,4-butane diol, dipropylene glycol, trimethylolmethane,trimethylolpropane, trimethylolethane, pentaerythritol,dipentaerythritol, glycerol, and substituted polyols such as monoallylglycerol. Examples of the polymeric polyols are polyether diols andpolyesterdiols such as polypropylene glycol, polybutylene glycol,polyethylene glycol, and polycaprolactone diol. Preferably the polyol isa diol. Mixtures of the aforesaid polyols may also be utilized. In apreferred embodiment polybutylene glycol either alone or in admixturewith polyethylene glycol and/or polypropylene glycol is utilized.

Examples of the active hydrogen-containing ethylenically unsaturatedcompound are a hydroxyalkyl acrylate or methacrylate. Suitable compoundsinclude 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxypropylmethacrylate, 3-hydroxypropyl methacrylate and the like. Preferably,2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate are utilized.

The diluent is used to reduce the concentration of thepolyurea-polyurethane polymer dispersion. Generally, any conventionaldiluent can be utilized herein although typically the diluent is anethylenically unsaturated compound free of active hydrogens. Examples ofthe ethylenically unsaturated compound free of active hydrogens arethose selected from the group consisting of vinyl aromatic compounds andalkylacrylates or methacrylates. Suitable compounds include styrene,vinyl toluene, methyl acrylate, ethyl acrylate, propyl acrylate,isopropyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexylacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate,butyl methacrylate and 2-ethyl-hexyl methacrylate. Preferably, styrene,methyl methacrylate, and butyl methacrylate are utilized.

It should be understood that, although each of the reactive componentsin the process for preparing the aforedescribed polyurea-polyurethanedispersion polymers has been discussed separately, the present inventionalso contemplates the use of a single compound having the functionalityof the polyol free of ethylenic unsaturation and the activehydrogen-containing polymerizable ethylenically unsaturated compound. Anexample of such a compound is glycerol monoacrylate.

The particle size of the polymer dispersions of the present inventioncan be determined from transmission light scattering measurements andapplication of the Mie Light Scattering Theory. A detailed discussion ofthis method can be found in P. E. Pierce and C. E. Cowan, "Measurementof Particle Size of Anionic Electrodeposition Resin Micelles and FactorsWhich Influence Micelle Size," Journal of Paint Technology, Vol. 44, No.568, pages 61-67, May 1972 and also E. A. Collins, J. A. Davidson, andC. A. Daniels, "Review of Common Methods of Particle Size Measurement,"Journal of Paint Technology, Vol. 47, No. 604, pages 35-56, May 1975.When the percent light transmittance is controlled to within the rangeof from about 20 percent to about 90 percent, the particle size of thedispersion broadly falls within the range of from about 200 Angstroms toabout 3000 Angstroms. The majority of the particles, however, are withinthe range of from about 400 Angstroms to about 600 Angstroms.

The dispersions of the present invention can also be characterized bytheir opaqueness which is characteristic of a dispersion. Moreover, thedispersions of the present invention exhibit a noticeable lack ofthixotropy which further distinguishes them over solution polymers. In apreferred embodiment the aforesaid dispersions can be furthercharacterized in that when one percent by weight of a polar solvent suchas dimethylformamide is added to the dispersion, the viscosity of thedispersion increases. This distinguishes the dispersion from solutionpolymers in which the addition of a polar solvent would cause aviscosity decrease.

The dispersion polymers of the present invention can be represented bythe following structural formula: ##STR1## wherein: R is the radicalderived from a polymerizable active hydrogen-containing ethylenicallyunsaturated compounds as mentioned above.

G is a bivalent organic radical derived from the removal of terminalhydrogen groups from a polyol free of ethylenic unsaturation, such asthose mentioned above, having a molecular weight between 62 and 5000.

Q is a bivalent organic radical derived from removal of terminalhydrogen groups from a polyfunctional amine, such as those mentionedabove, containing primary and/or secondary amino groups having amolecular weight between 60 and 2000.

B is a bivalent organic radical derived from removal of terminalisocyanate groups from an organic polyisocyanate such as those mentionedabove.

On an average basis m=0.75 to 10 and n=1.

The polymerizable ethylenically unsaturated urea-urethane polymerdispersions of the present invention can be prepared in a one stepreaction in the following manner. A polyisocyanate is contacted with apolyfunctional amine containing primary and/or secondary amino groups inthe presence of a polyol free of ethylenic unsaturation, a diluent, andan active hydrogen-containing polymerizable ethylenically unsaturatedcompound under conditions sufficient to form a polymerizableethylenically unsaturated urea-urethane polymer dispersed in thepolymerizable ethylenically unsaturated compound.

Preferably the dispersion polymers described above are prepared in a twostep reaction; for example, in the first step the polyisocyanate iscontacted with the polyfunctional amine in the presence of the polyolfree of ethylenic unsaturation and the diluent under conditionssufficient to form a NCO-group containing polyurea-polyurethanedispersed in an ethylenically unsaturated compound. In the second step,the active hydrogen-containing ethylenically unsaturated compound iscontacted with the NCO-group containing dispersion polymer formed in thefirst step to end-cap the polymer with polymerizable ethylenicunsaturation. Preferably, a portion of the active hydrogen-containingethylenically unsaturated compound is present in the first step and aportion of the polyol free of ethylenic unsaturation is present in thesecond step. Under this type of procedure problems with viscosityvariation and foaming as a result of contamination with water can becontrolled. By prereacting about three-fourths of the activehydrogen-containing ethylenically unsaturated compound, prior to formingthe dispersion a portion of the diisocyanate is initially capped at oneend to better control chain length. In a further preferred embodimentthe polyfunctional amine and polyol are premixed before being contactedwith the polyisocyanate. Moreover, some polyol can be withheld duringthe dispersion forming step and added prior to completion of end-cappingfor viscosity adjustment. Low viscosity resins can readily be producedin this manner.

It should be understood that although the disclosure has focused on adetailed discussion of particular embodiments of both the one-step andtwo-step reactions, the invention is not to be thusly limited. Rather,other equivalent embodiments are contemplated by the present inventionand fall within the scope of the claims. For example, in one embodimentpolyisocyanate, polyfunctional amine, polyol free of ethylenicunsaturation, and dilent are reacted to form a hydroxyl rich prepolymerwhich is reacted with additional polyisocyanate prior to end-cappingwith active hydrogencontaining ethylenically unsaturated compound.

In preferred embodiments of both the one-step and two-step reactions,the ethylenic unsaturation in the resultant polymerizable ethylenicallyunsaturated ureaurethane polymer is in the terminal position.

The polymer is usually present in the active hydrogen-free ethylenicallyunsaturated dispersion medium to the extent of about 25 percent to about80 percent resin solids. The amount of polymer forming reactantsutilized in preparing the claimed polymers can vary, but generally theequivalent ratio of isocyanate to active hydrogen in the polyol andpolyfunctional amine is within the range of 1.1 to 2.0/1, and theequivalent ratio of polyol to polyfunctional amine is within the rangeof 0.75 to 20/1. Preferably, the equivalent ratio of isocyanate toactive hydrogen and combined polyol and polyfunctional amine is withinthe range of 1.2 to 1.4/1; the preferred equivalent ratio of polyol topolyfunctional amine is within the range of 1 to 15/1. Other ingredientsare typically utilized with the polymer forming components describedabove, such as free radical inhibitors to prevent premature reaction ofthe ethylenically unsaturated compound and catalyst to accelerate thereaction between polyol and polyisocyanate. These materials aretypically present in small amounts, generally from about 0.01 percent toabout 1 percent by weight.

The dispersions of the present invention are useful in moldingapplications such as injection molding and in the formulation of in-moldcoatings. In-mold coating compositions are applied to the outer surfaceof molded articles to cover surface defects such as sink marks,porosity, microcracks and open knit lines. In-mold coatings generallymust possess certain characteristics. Among these, the compound must beable to flow under pressure to cover the article completely with auniform skin. The viscosity must not be low enough, however, that thecompound will be squeezed out of the mold during the press closing.Particularly, the composition must have the ability to form a film thatadheres well to a fiber glass reinforced substrate even with no priortreatment of the substrate surface; this must be so even if thesubstrate has defects or is damaged. Also, the cured coating mustrelease easily from the chromed surfaces of the mold. The in-moldcoating compositions of the present invention are especially useful inall these respects.

The in-mold coating compositions of the present invention are formulatedby combining a catalyst and a mold release agent to the dispersionpolymers as described above. The coating composition must be capable ofbeing applied to the outer surface of a molded article while still inthe mold such that when the mold is closed and sufficient pressureapplied the coating composition substantially and uniformly covers andpenetrates the article surface.

The dispersion medium for the in-mold coating composition is theethylenically unsaturated monomer selected from those mentioned above.Suitable monomers include styrene, alpha-methyl styrene, vinyl toluene,and methyl methacrylate. Preferably a vinyl aromatic compound such asstyrene is utilized. The ethylenically unsaturated monomer is usuallypresent in amounts of from about 5 to 50 percent by weight based ontotal weight of the coating composition.

The polymerizable ethylenically unsaturated urea-urethane polymer hasbeen discussed in detail above therefore no further discussion will begiven here. The urea-urethane polymer is present in amounts of fromabout 5 to about 50 percent by weight, preferably 10 to 40 percent byweight based on total weight of the composition.

There are many catalysts which are conventionally utilized in moldingcompositions and one generally can use any number of these. Typically, afree radical generating catalyst such as peroxide is utilized tocatalyze the crosslinking reaction. Examples of free radical catalystsinclude tertiary butyl perbenzoate, tertiary butyl peroctoate, methylethyl ketone peroxide, and mixtures thereof. Preferred catalysts aretertiary butyl perbenzoate, tertiary butyl peroctoate, and mixturesthereof. The free radical generating catalyst is present in minoramounts, usually about 0.5 to 3 percent by weight based on total weightof the composition.

The mold release agent is a common additive under standard moldingpractice. It functions as an external lubricant so that after molding iscompleted and the mold is opened the coated article can be removedreadily with a minimum of handling and therefore a reduced incidence ofscratching or abrasion. There are many types of mold release agentsconventionally used in molding compounds and one generally can use anynumber of these. Examples of suitable materials include zinc stearate,the natural product lethicin and DuPont's ZELEC UN aliphatic phosphate;preferably ZELEC UN is utilized.

In one embodiment the in-mold coating composition additionally containsa pigment. The pigment component is added in amounts of from 0 percentto about 80 percent by weight, preferably 10 to 40 percent by weightbased on the total weight of the composition. Preferably anelectroconductive pigment, such as conductive carbon black is used toimpart conductivity to the in-mold coating. This facilitates the use ofelectrostatically applied coating compositions over the in-mold coating.Although the use of an electroconductive pigment is preferred, anonconductive in-mold coating can be produced with the use ofconventional nonconductive inorganic pigments. Useful pigments includetitanium dioxide, silica, iron oxides, talc, mica, clay, carbon black,zinc oxide, lead chromate and calcium carbonate. If desired organicpigments can also be utilized.

In a preferred embodiment, the in-mold coating composition of thepresent invention additionally contains an ethylenically unsaturatedpolyurethane which is free of urea linkages formed by reacting an activehydrogen-containing unsaturated compound, a polyester polyol, and apolyisocyanate. This polyurethane functions as a flexible crosslinkingmonomer. Examples of suitable polyisocyanates and activehydrogen-containing unsaturated compounds include those mentioned abovein connection with the preparation of the urea-urethane polymers.

Examples of suitable polyester polyols include those formed by theesterification of polyols with polycarboxylic acids including acidanhydrides. The polyols conventionally employed in making the polyesterpolyols include alkylene glycols such as ethylene glycol, propyleneglycol, and neopentyl glycol and glycols such as cyclohexanedimethanoland polyether glycols, e.g., poly(oxytetramethylene) glycol. Mixtures ofglycols can also be used. Suitable polycarboxylic acids includeisophthalic acid, phthalic anhydride, adipic acid and azaleic acid.Polyester polyols can also be made from the reaction of a lactone withan alcohol or polyol. The lactones commercially available arerepresented by the structure: ##STR2## where n is from 2 to 9 and theR's are hydrogen, alkyl, cycloalkyl, alkoxy and single ring aromatichydrocarbon radicals. Preferred lactones are epsilon-caprolactones wheren=5. Examples of polyols are those described above. Also, the activehydrogen-containing ethylenically unsaturated compound can be used toring open the lactone and form the polyester.

In a one embodiment the aforesaid polyurethane crosslinker is producedfrom 2-hydroxyethyl methacrylate (HEMA), epsilon-caprolactone, andtoluene diisocyanate at a mole ratio of 1:3:0.5 respectively asdisclosed in U.S. Pat. No. 4,188,472 to Chang, issued Feb. 12, 1980 andentitled "Curable Lactone Derived Resins". The HEMA ring opens thelactone and the two open chains then react with the diisocyanate to forma urethane diacrylate. The ethylenically unsaturated polyurethane freeof urea linkages is usually present in amounts of from about 5 to about50 percent by weight, preferably 10 to 40 percent by weight based ontotal weight of the composition.

The in-mold coating process comprises four steps, namely:

(a) placing on the outer surface of said article in a mold a charge ofthe curable thermosetting coating composition set forth above. Thecharge is sufficient to provide on said surface a coating having athickness of less than about 20 mils.

(b) applying sufficient pressure to said charge to cause the coatingcomposition to substantially and uniformly cover and penetrate saidsurface,

(c) curing said coating composition in said mold under heat and pressureto bond said coating composition to said surface; and

(d) removing said coated article from said mold, providing said articlewith a substantially smooth defect-free crosslinked polyurea-urethanebased coating bonded to said surface of said article.

The claimed in-mold coating composition can be applied by the aboveprocess to any thermoset article, but it is particularly useful forcoating fiber glass reinforced Sheet Molding Compounds, for examplefiber glass reinforced unsaturated polyester based Sheet MoldingCompound.

An amount of the in-mold coating composition is charged to a moldedthermoset article in a mold such that it is applied in a thin layer,typically less than 20 mils, preferably from about 0.5 to about 10 mils.Once the mold is closed sufficient pressure is applied to cause thecoating to substantially and uniformly cover and penetrate the articlesurface, generally, from about 50 psi to about 3000 psi. The in-moldcoating is cured at a temperature of from about 50° C. to about 200° C.for about 15 seconds to 5 minutes and finally the mold opened and thecoated article released. Articles coated in this manner exhibitexcellent surface quality free of defects, good chip resistance, goodadhesion of coating to substrate and good intercoat adhesion between themolded coating and subsequently applied coating compositions.

Besides use in in-mold coating compositions the dispersions of thepresent invention are useful in the formulation of injection moldingcompositions. In addition to the dispersion, the molding compositionscontain a mold release agent and reinforcements.

The molding composition must be capable of being injected into a mold ina smooth even flow and cured therein. The dispersion medium for theinjection molding composition is an ethylenically unsaturated monomersuch as those mentioned above in connection with the preparation of theurea-urethane polymer dispersions. Suitable monomers include styrene,alpha-methyl styrene, vinyl toluene and methyl methacrylate. Preferablya vinyl aromatic compound such as styrene is used. The ethylenicallyunsaturated monomer is usually present in amounts of from 5 to 50percent by weight based on total weight of the coating composition. Thepolymerizable ethylenically unsaturated urea-urethane polymer has beendescribed in detail above thus no further discussion need be given here.The urea-urethane polymer is present in amounts of from about 10 percentto about 85 percent by weight, preferably 20 to 75 percent by weightbased on the total weight of the composition.

Examples of mold release agents are those mentioned above in thedescription of the in-mold coating compositions. Preferably DuPont'saliphatic phosphate ZELEC UN is used. The mold release agent is used inamounts of from about 0.01 to about 5 percent by weight based on totalweight of the coating composition.

The reinforcements are added to improve physical properties such astensile strength, heat sag, and stiffness properties. Reinforcements canbe of any conventional type and include fiberous reinforcements,non-fiberous reinforcements, and fillers. Useful fillers include calciumcarbonate, clay, talc, and hydrated alumina. Useful non-fiberousreinforcements include hammer-mill glass flakes, suzorite mica, andwollastonite. Typically fiberous reinforcements such as glass fillersare utilized. The fibers are typically very short, generally 1/4 inch orless and they comprise from about 0.5 percent to about 75 percent byweight, preferably 5 to 40 percent by weight based on the total weightof the composition. In a preferred embodiment fiber glass, particularlymilled fiber glass is utilized to reinforce the molding composition.Other fiberous materials such as graphite fiber can also be used.

In a preferred embodiment the injection molding composition of thepresent invention additionally contains an ethylenically unsaturatedpolyurethane which is free of urea linkages and which is formed fromreacting an organic polyisocyanate with an active hydrogen containingunsaturated compound. Examples of suitable polyisocyanates and activehydrogen containing ethylenically unsaturated compounds include thosementioned above in connection with the preparation of the urea-urethanepolymers. This ethylenically unsaturated urethane is a crosslinker whichstiffens the resultant molding. As a result the flexural modulus andheat distortion temperature are improved. When used it is used inamounts of from about 1 percent to about 50 percent by weight,preferably 5 to 30 percent by weight based on total weight of thecomposition.

Other optional components included in the claimed injection moldingcomposition include free radical generating catalyst which has beendiscussed above and surfactant such as a silicone surfactant. When usedthese ingredients are used in amounts of about 0.1 to 5 percent byweight based on total weight of the composition.

The present invention also relates to a method of providing an injectionmolded completely cured thermoset article. For injection molding, ingeneral, either a thermoplastic or thermosetting resin based moldingcomposition is forced under pressure from a heated chamber through afeeding channel into the cavity of an injection mold. The mold is closedand the composition is solidified into a molded article.

The process of molding comprises the following steps:

(a) depositing in a mold a charge of a thermosetting molding compositionsuch as set forth above;

(b) heating the charge while in the mold so as to cure it and form athermoset article; and

(c) removing the article from the mold.

The amount of molding composition charged to the mold must be sufficientto substantially fill the mold. The mold is closed and sufficient heatis applied to solidify the molding composition into cured article,generally from about 50° C. to about 200° C., preferably 75° C. to 185°C. are utilized. The resultant molded article has an integrally moldedouter surface shaped in the reverse image of the mold. The articlesmolded in this manner have excellent surface quality and exhibitexcellent adhesion to applied coating compositions.

Because of the desirable viscosity and thixotropy characteristics of theurea-urethane polymers they are very useful in injection molding inwhich the molding composition is deposited in the mold by forcing itunder pressure from a reservoir through a feeding channel into thecavity of the mold. For use in injection molding, the moldingcompositions preferably have a viscosity of about 25,000 to 350,000centipoises (measured at 25° C.) and lack substantial thixotropy.

Besides injection molding, the compositions of the invention can also beused in conventional compression molding where high viscosity can betolerated. In compression molding both heat and pressure are used in themolding. Typical pressures utilized range from about 50 to 3000 psi.

Although the invention has been described with specific references andspecific details of embodiments thereof, it is to be understood that itis not intended to be so limited since changes and alterations thereinmay be made by those skilled in the art which are within the fullintended scope of this invention as defined by the appended claims.

    ______________________________________                                                                 Parts by                                             Charge   Reactants       Weight (grams)                                       ______________________________________                                        A        isophorone diisocyanate                                                                       495                                                           methyl methacrylate                                                                           1078                                                          methyl quinone  0.3                                                           IONOL.sup.1      1                                                   B        POLYMEG 1000.sup.2                                                                            1320                                                          isophoronediamine                                                                              75                                                  C        dibutyltin dilaurate                                                                           3                                                   D        methyl methacrylate                                                                           924                                                  E        2-hydroxyethyl acrylate                                                                       112                                                  ______________________________________                                         .sup.1 2,6di-tertiary butyl paracresol available from Shell Chemical          Company.                                                                      .sup.2 Polytetramethylene ether glycol having a molecular weight of 1000      available from Quaker Oats Company (hereinafter referred to as                polybutylene glycol).                                                    

A reactor was charged with (A), while stirring. Subsequently, (B) wasadded over a one hour period at 25° C.-30° C. followed by heating to 60°C.-70° C. The reaction mixture was held at this temperature for one hourfollowed by the addition of (C). The reaction mixture was held at 50°C.-60° C. for one-half hour and then (D) was added to bring the mixtureto 50 percent methyl methacrylate content. Subsequently, (E) was addedand the reaction mixture was heated until all NCO was reacted asdetermined by Infrared Spectroscopy. The resultant polyurea-polyurethaneacrylate dispersion constituted about 50 percent polymer in about 50percent methyl methacrylate. Brookfield viscosity determinations withnumber 3 spindle at 2 and 20 RPM yielded viscosities of 4750 and 4650centipoises, respectively.

EXAMPLE II

    ______________________________________                                                                 Parts by                                             Charge   Reactants       Weight (grams)                                       ______________________________________                                        A        toluene diisocyanate                                                                          2690                                                          methyl methacrylate                                                                           6302                                                          methyl quinone   2                                                            IONOL            8                                                   B        2-hydroxyethyl acrylate                                                                       538                                                  C        POLYMEG 1000    7733                                                          isophoronediamine                                                                             526                                                  D        dibutyltin dilaurate                                                                           18                                                  E        POLYMEG 1000    619                                                           methyl methacrylate                                                                           333                                                   E1      POLYMEG 1000    309                                                           methyl methacrylate                                                                           166                                                  F        2-hydroxyethyl acrylate                                                                       216                                                  ______________________________________                                    

A reactor was charged with (A), while stirring. To this mixture (B) wasadded, at room temperature, while monitoring the temperature to ensurethat it did not exceed 60° C. Subsequently, (C) was added over a onehour period at 25° C.-30° C. followed by heating to 60° C.-70° C. Thereaction mixture was held at this temperature for one hour followed bythe addition of (D). After one-half hour the NCO equivalent weight andBrookfield viscosity were determined. The viscosity value was less than25,000 centipoises therefore additional polybutylene glycol and methylmethacrylate were added to adjust the viscosity. These additions,constituted charges E and E1. The viscosity value after the addition ofE1 was 26,000 centipoises. End-capping was completed with the additionof F. The reaction mixture was then held at 60° C.-70° C. until all NCOwas reacted as determined by Infrared Spectroscopy. The resultantpolyurea-polyurethane acrylate dispersion constituted about 65 percentpolymer in about 35 percent methyl methacrylate. The polymer had aweight average molecular weight of 16,400 as determined by gelpermeation chromatography using a polystyrene standard (polymerdissolved in dimethylformamide). Preferred polymers typically will havemolecular weight determined by this procedure of 10,000 to 30,000.Brookfield viscosity determinations with number 6 spindle at 2, 10, and20 RPM yielded viscosities of 25,000; 25,000; and 23,000 centipoises,respectively.

EXAMPLE III

    ______________________________________                                                                 Parts by                                             Charge   Reactants       Weight (grams)                                       ______________________________________                                        A        toluene diisocyanate                                                                          750                                                           methyl methacrylate                                                                           1292                                                          methyl quinone  0.3                                                           IONOL            2                                                   B        2-hydroxyethyl acrylate                                                                       150                                                  C        CARBOWAX 600.sup.1                                                                            1293                                                          isophoronediamine                                                                             147                                                  D        dibutyltin dilaurate                                                                           4                                                   E        CARBOWAX 600    52                                                            methyl methacrylate                                                                           28                                                    E1      CARBOWAX 600    52                                                            methyl methacrylate                                                                           28                                                    E2      CARBOWAX 600    52                                                            methyl methacrylate                                                                           28                                                    E3      CARBOWAX 600    52                                                            methyl methacrylate                                                                           28                                                   F        2-hydroxyethyl acrylate                                                                       60                                                   ______________________________________                                         .sup.1 Polyethylene glycol having a molecular weight of 600 available fro     Union Carbide.                                                           

A reactor was charged with (A) at room temperature, with stirring. Tothis mixture was added (B) at room temperature. Subsequently, (C) wasadded over a one hour period at 25° C.-30° C. followed by heating to 60°C.-70° C. The reaction mixture was held at this temperature for one hourfollowed by the addition of (D). After one-half hour the NCO equivalentweight and Brookfield viscosity were determined. The viscosity value was1300 centipoises therefore additional polyethylene glycol and methylmethacrylate were added to adjust the viscosity. These additionsconstituted charges (E), (E1), (E2), and (E3). The viscosity value afterthe addition of E3 was 10,200 and end-capping was completed with theaddition of F. The reaction mixture was then held at 60° C.-70° C. untilall NCO was reacted as determined by Infrared Spectroscopy. Theresultant polyurea-polyurethane acrylate dispersion constituted 65percent polymer in about 35 percent methyl methacrylate. Brookfieldviscosity determinations with number 5 spindle at 2, 10 and 20 RPMyielded viscosities of 7,000; 7,600; and 7,200, respectively.

EXAMPLE IV

    ______________________________________                                                                 Parts by                                             Charge   Reactants       Weight (grams)                                       ______________________________________                                        A        toluene diisocyanate                                                                          552                                                           butyl methacrylate                                                                            2292                                                          methyl quinone  0.4                                                           IONOL            2                                                   B        2-hydroxyethyl acrylate                                                                       110                                                  C        POLYMEG 1000    1586                                                          isophoronediamine                                                                             108                                                  D        dibutyltin dilaurate                                                                           4                                                   E        POLYMEG 1000    200                                                           butyl methacrylate                                                                            108                                                  F        2-hydroxyethyl acrylate                                                                        44                                                  ______________________________________                                    

A reactor was charged with (A), while stirring. To this mixture wasadded (B) at room temperature. Subsequently, (C) was added over a onehour period at 25° C.-30° C. followed by heating to 60° C.-70° C. Thereaction mixture was held at this temperature for one hour followed bythe addition of (D). After one-half hour the NCO equivalent weight andBrookfield viscosity were determined. The viscosity value was less than25,000 centipoises and additional polybutylene glycol and butylmethacrylate were added to adjust the viscosity. This addition wascharge E and after one-half hour the NCO equivalent weight andBrookfield viscosity were redetermined. The viscosity value was 60,000centipoises and end-capping was completed with the addition of (F). Thereaction mixture was held at 60° C.-70° C. until all NCO was reacted asdetermined by Infrared Spectroscopy. The resultant polyurea-polyurethaneacrylate dispersion constituted about 65 percent polymer in about 35percent butyl methacrylate. Brookfield viscosity determinations withnumber 7 spindle at 2, 10, and 20 RPM yielded viscosities of 50,000;48,000; and 50,000, respectively.

EXAMPLE V

    ______________________________________                                                                 Parts by                                             Charge   Reactants       Weight (grams)                                       ______________________________________                                        A        toluene diisocyanate                                                                          618                                                           methyl methacrylate                                                                           1292                                                          methyl quinone  0.4                                                           IONOL            1                                                   B        2-hydroxyethyl acrylate                                                                       88                                                   C        CARBOWAX 600    1065                                                          POLYMEG 1000    507                                                           isophoronediamine                                                                             86                                                   D        dibutyltin dilaurate                                                                          37                                                   E        CARBOWAX 600    30                                                            methyl methacrylate                                                                           16                                                    E1      CARBOWAX 600    30                                                            methyl methacrylate                                                                           16                                                    E2      CARBOWAX 600    30                                                            methyl methacrylate                                                                           16                                                   F        2-hydroxyethyl acrylate                                                                       36                                                   ______________________________________                                    

A reactor was charged with (A) at room temperature, while stirring. Tothis mixture was added (B) at room temperature. Subsequently, (C) wasadded over a one hour period at 25° C.-30° C. followed by heating to 60°C.-70° C. The reaction mixture was held at this temperature for one hourfollowed by the addition of (D). After one-half hour the NCO equivalentweight and Brookfield viscosity were determined. The viscosity value was3100 centipoises and additional polyethylene glycol and methylmethacrylate were added to adjust the viscosity. These additionsconstituted charges (E), (E1), and (E2). The viscosity after theaddition of E2 was 16,100 centipoises. End-capping was completed withthe addition of (F). The reaction mixture was then held at 60° C.-70° C.until all NCO was reacted as determined by Infrared Spectroscopy. Theresultant polyurea-polyurethane acrylate dispersion constituted 65percent polymer in 35 percent methyl methacrylate. Brookfield viscositydeterminations with number 5 spindle at 2, 10, and 20 RPM yieldedviscosities of 14,000; 14,400; and 14,350, respectively.

EXAMPLE VI

    ______________________________________                                                                 Parts by                                             Charge   Reactants       Weight (grams)                                       ______________________________________                                        A        toluene diisocyanate                                                                          504                                                           methyl methacrylate                                                                           1292                                                          methyl quinone  0.4                                                           IONOL            1                                                   B        2-hydroxyethyl acrylate                                                                       101                                                  C        POLYMEG 1000    1737                                                          ethylene diamine                                                                              17                                                   D        dibutyltin dilaurate                                                                          37                                                   E        POLYMEG 1000    116                                                           methyl methacrylate                                                                           62                                                   F        POLYMEG 1000    58                                                            methyl methacrylate                                                                           31                                                   G        2-hydroxyethyl acrylate                                                                       41                                                   ______________________________________                                    

A reactor was charged with (A) at room temperature, while stirring. Tothis mixture was added (B) at room temperature. Subsequently, (C) wasadded over a one hour period at 25° C.-30° C. followed by heating to 60°C.-70° C. The reaction mixture was held at this temperature for one hourfollowed by the addition of (D). After one-half hour the NCO equivalentweight and Brookfield viscosity were determined. The viscosity value was9000 centipoises and additional polyethylene glycol and methylmethacrylate were added to adjust the viscosity. These additionsconstituted charges (E) and (F). The viscosity after the addition of (F)was 22,000 centipoises. End-capping was completed with the addition of(G). The reaction mixture was then held at 60° C.-70° C. until all NCOwas raacted as determined by Infrared Spectroscopy. The resultantpolyurea-polyurethane acrylate dispersion constituted 65 percent polymerin 35 percent methyl methacrylate. Brookfield viscosity determinationswith number 7 spindle at 2, 10, and 20 RPM yielded viscosities of190,000; 104,000; and 82,000, respectively.

EXAMPLE VII Part I

Part I of this example illustrates the preparation of an in-mold coatingcomposition using as the base resin polyurea-polyurethane acrylatedispersion prepared in the manner taught by the previous examples.

    ______________________________________                                                                 Parts by                                             Reactants                Weight (grams)                                       ______________________________________                                        Polyurea-polyurethane acrylate resin dispersion.sup.1                                                  22                                                   Flexible crosslinker.sup.2                                                                             22                                                   Styrene                  9                                                    Calcium Carbonate        44                                                   Mold Release Agent.sup.3 0.14                                                 Catalyst Promoter.sup.4  0.11                                                 Carbon Black             3                                                    ______________________________________                                         .sup.1 This dispersion was prepared in the manner taught by Example I fro     toluene diisocyanate, isophoronediamine, polypropylene glycol and             2hydroxyethyl acrylate at 65 percent polymer in 35 percent styrene.           .sup.2 Urethane diacrylate of hydroxyethyl                                    methacrylate/epsiloncaprolactone adduct. This diacrylate has the followin     composition: hydroxyethyl methacrylate, epsiloncaprolactone and toluene       diisocyanate at a mole ratio of 1:3:0.5, respectively.                        .sup.3 ZELEC UN available from DuPont.                                        .sup.4 Cobalt octoate, available from Mooney Chemical.                   

To prepare the in-mold coating composition, a carbon black pasteconcentrate was initially prepared in the urethane diacrylateflexibilizer and one half of the styrene. The paste was milled to aHegman grind of 6⁺ followed by the addition of the polyurea-polyurethaneacrylate dispersion resin. Calcium carbonate was milled into the mixturefollowed by the addition of the ZELEC UN mold release agent and thepromoter. The remainder of the styrene was used for washing theequipment once the composition was prepared.

Part II

Part II of this example illustrates the use of the in-mold coatingcomposition prepared in Part I to coat an article which was compressionmolded from a sheet molding compound.

Initially, the in-mold coating composition prepared in Part I wascatalyzed by mixing together 100 grams of the in-mold coatingcomposition and 1.8 grams of tertiary butyl perbenzoate catalyst. (Thiscoating composition is stable for over 14 days at 25° C. or over onehour at 80° C.). Subsequently, 450 grams of fiber glass reinforcedunsaturated polyesterbased Sheet Molding Compound (SMC) was charged to a12 inch×12 inch plaque mold which was preheated to a temperature withinthe range 145° C. to 155° C. The mold was pressured to about 1000 psiand the Sheet Molding Compound was molded and cured into a 0.125 inchplaque in about 90 seconds. Subsequently, the mold was opened and about30 grams of catalyzed in-mold coating composition was charged onto theplaque's surface. The mold was closed and repressured, the coatingcomposition covered the plaque surface in a 3 to 5 mil film, and finallywas cured in about one minute. The mold was reopened and a SMC articlewith a conductive, porosity-free surface was removed. The in-moldcoating composition utilized in this example exhibited excellentadhesion to all SMC substrates tested, good chip resistance and enoughconductivity to be coated with electrostatically applied coatings.Intercoat adhesion between the molded coating and subsequently appliedcoating compositions was excellent.

EXAMPLE VIII Part I

Part I of the example illustrates the preparation of an injectionmolding composition using as the base resin polyurea-polyurethaneacrylate dispersion prepared in the manner taught by the previousexamples.

    ______________________________________                                        Reactants              Parts by Weight                                        ______________________________________                                        Polyurea-polyurethane, acrylate resin                                                                72                                                     dispersion of Example II                                                      Crosslinker.sup.1      27                                                     Catalyst.sup.2         1                                                      Silicone surfactant.sup.3                                                                            1                                                      MONDUR MP.sup.4        0.4                                                    Mold release agent.sup.5                                                                             0.4                                                    MFG 1/8 inch.sup.6     37                                                     ______________________________________                                         .sup.1 An ethylenically unsaturated polyurethane diacrylate free of urea      linkages and formed by reacting the following ingredients                

                               Parts by                                           Charge   Reactants         Weight (grams)                                     A        MONDUR MR         6944                                                        Dibutyltin dilaurate                                                                            9                                                           Silicone surfactant                                                                             2                                                           Methyl quinone    2                                                           IONOL             8                                                  B        2-hydroxyethyl methacrylate                                                                     7466                                               C        Styrene           3600                                                A twentytwo liter reactor was charged with (A) and part of (B) followed b     the addition of (C) in two 1800 gram additions about ten minutes apart.       The remainder of (B) was added and the mixture was heated to 60°       C.-70° C., slowly for about five hours and then allowed to cool.       The resultant polyurethane had a viscosity of Z.sup.3. Infrared               spectroscopy revealed the absence of isocyanate groups.                       .sup.2 1,1di-tertiary butylperoxy 3,3,5trimethylcyclohexane.                  .sup.3 Available from Union Carbide as UC 31995.                              .sup.4 Crude methylene diphenyl diisocyanate available from Mobay Chemica     Corp.                                                                         .sup.5 ZELEC UN available from DuPont.                                        .sup.6 Milled fiber glass passed through a 1/8 inch screen.              

The injection molding composition was prepared as follows. A mixingvessel equipped with a rotary mixing blade was charged withpolyurea-polyurethane acrylate resin dispersion, crosslinker, catalyst,silicone surfactant and mold release agent and the charge blended untilhomogenous. As the aforesaid mixture was stirred the MONDUR MR andmilled fiber glass were added followed by additional stirring until themixture was uniform. Subsequently, the mixture was allowed to stir foran additional period enabling air to be dispersed within it.

Part II

Part II of this example illustrates the use of the injection moldingcomposition of Part I for injection molding.

The molding composition was processed on an Accuratio Reaction InjectionMolding Machine VR-75. This machine is a two pot system designed toprocess polyols and isocyanates as in polyurethane molding. Since themolding composition of this example is a one component composition onlyone side of the Reaction Injection Machine was charged while one sidewas blocked off.

The molding composition was charged into an air pressurized tank and thesystem purged of air and solvent by recirculation through a detachedline until clear. The injection head was bolted to an aluminum RIM testplaque mold installed in a 30 ton vertical hydraulic press andelectrically heated to 105° C.±5° C. The machine dispensed about 300grams of the molding mix to fill a 12 inch×12 inch×1/8 inch mold. Thecomposition was cured for one minute at about 110° C. Surface quality ofthe cured plaques was Class A and was immediately paintable withexcellent paint adhesion. The chart below lists some typical physicalproperties of the aforesaid injection molded compositions.

    ______________________________________                                        Tensile Strength × 10.sup.3 psi                                                                      2.14                                             Tensile Modulus × 10.sup.5 psi                                                                       1.93                                             Flexural Strength Parallel to Flow × 10.sup.3 psi                                                    3.71                                             Flexural Modulus Parallel to Flow × 10.sup.5 psi                                                     2.25                                             Flexural Strength Perpendicular to Flow × 10.sup.3                                                   3.07                                             Flexural Modulus Perpendicular to Flow × 10.sup.5                                                    1.48                                             Notched Izod ft lbs/in       1.38                                             Percent Elongation           20.9                                             Heat Distortion Iemperature (264 psi)                                                                      125°                                      Linear Coefficient of Tnermal Expansion                                       Parallel to Flow IN/IN/°F. × 10.sup.6                                                         29.7                                             Heat Sag 6 inches at 121° C. for 30 minutes                                                         0.17                                             Parallel to Flow (in inches)                                                  Heat Sag 6 inches at 121° C. for 30 minutes                                                         0.55                                             Perpendicular to Flow (in inches)                                             ______________________________________                                    

What is claimed is:
 1. An article having a coating on its outer surfacewhich substantially and uniformly covers the surface, the coatingcomprising an at least partially cured coating composition whichcomprises a dispersion of the following ingredients in an ethylenicallyunsaturated monomer:(i) a polymerizable ethylenically unsaturatedurea-urethane polymer prepared by a process, which comprises:A. reactinga polyisocyanate, at least a portion of which is a diisocyanate, with apolyfunctional amine containing primary and/or secondary amino groups inthe presence of a polyol, at least a portion of which is a polymericpolyol, free of ethylenic unsaturation and a diluent which is anethylenically unsaturated compound free of active hydrogens, theequivalent ratio of isocyanate to active hydrogen in said polyol andsaid polyfunctional amine being within the range of 1.1 to 2.0/1 and theequivalent ratio of polyol to polyfunctional amine being within therange of 0.75 to 20/1, under conditions sufficient to form an NCOgroup-containing polyurea-polyurethane dispersed in an ethylenicallyunsaturated compound; followed by B. reacting the NCO group-containingpolyurea-polyurethane dispersion with an active hydrogen-containingpolymerizable ethylenically unsaturated compound under conditionssufficient to react the NCO-functionality with the active hydrogensthereby forming the polymerizable ethylenically unsaturatedurea-urethane polymer dispersion; (ii) a catalyst, and (iii) a moldrelease agent.
 2. The article of claim 1 wherein the coating compositionadditionally contains pigment.
 3. The article of claim 1 wherein theethylenic unsaturation in the polymerizable ethylenically unsaturatedurea-urethane polymer is in the terminal position.
 4. The article ofclaim 1 wherein the catalyst is a free radical generating catalyst. 5.The article of claim 1 wherein the coating composition contains as anadditional ingredient an ethylenically unsaturated urethane free of urealinkages.
 6. The article of claim 2 wherein the pigment is anelectroconductive pigment.
 7. The article of claim 1 wherein thepolyfunctional amine is a diamine.
 8. The article of claim 1 wherein thepolyol is a diol.
 9. The article of claim 1 wherein a portion of theactive hydrogen-containing polymerizable ethylenically unsaturatedcompound is present in Step A.
 10. The article of claim 9 wherein aportion of the diol is present in Step B.